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Schuntermann DB, Jaskolowski M, Reynolds NM, Vargas-Rodriguez O. The central role of transfer RNAs in mistranslation. J Biol Chem 2024:107679. [PMID: 39154912 DOI: 10.1016/j.jbc.2024.107679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 08/20/2024] Open
Abstract
Transfer RNAs (tRNA) are essential small non-coding RNAs that enable the translation of genomic information into proteins in all life forms. The principal function of tRNAs is to bring amino acid building blocks to the ribosomes for protein synthesis. In the ribosome, tRNAs interact with messenger RNA (mRNA) to mediate the incorporation of amino acids into a growing polypeptide chain following the rules of the genetic code. Accurate interpretation of the genetic code requires tRNAs to carry amino acids matching their anticodon identity and decode the correct codon on mRNAs. Errors in these steps cause the translation of codons with the wrong amino acids (mistranslation), compromising the accurate flow of information from DNA to proteins. Accumulation of mutant proteins due to mistranslation jeopardizes proteostasis and cellular viability. However, the concept of mistranslation is evolving, with increasing evidence indicating that mistranslation can be used as a mechanism for survival and acclimatization to environmental conditions. In this review, we discuss the central role of tRNAs in modulating translational fidelity through their dynamic and complex interplay with translation factors. We summarize recent discoveries of mistranslating tRNAs and describe the underlying molecular mechanisms and the specific conditions and environments that enable and promote mistranslation.
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Affiliation(s)
- Dominik B Schuntermann
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5 HPK H10, 8093 Zurich, Switzerland
| | - Mateusz Jaskolowski
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5 HPK H10, 8093 Zurich, Switzerland
| | - Noah M Reynolds
- School of Integrated Sciences, Sustainability, and Public Health, University of Illinois Springfield, Springfield, Illinois, USA
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, Connecticut 06030-3305, USA.
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2
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Correia I, Oliveira C, Reis A, Guimarães AR, Aveiro S, Domingues P, Bezerra AR, Vitorino R, Moura G, Santos MAS. A Proteogenomic Pipeline for the Analysis of Protein Biosynthesis Errors in the Human Pathogen Candida albicans. Mol Cell Proteomics 2024; 23:100818. [PMID: 39047911 DOI: 10.1016/j.mcpro.2024.100818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 03/20/2024] [Accepted: 07/19/2024] [Indexed: 07/27/2024] Open
Abstract
Candida albicans is a diploid pathogen known for its ability to live as a commensal fungus in healthy individuals but causing both superficial infections and disseminated candidiasis in immunocompromised patients where it is associated with high morbidity and mortality. Its success in colonizing the human host is attributed to a wide range of virulence traits that modulate interactions between the host and the pathogen, such as optimal growth rate at 37 °C, the ability to switch between yeast and hyphal forms, and a remarkable genomic and phenotypic plasticity. A fascinating aspect of its biology is a prominent heterogeneous proteome that arises from frequent genomic rearrangements, high allelic variation, and high levels of amino acid misincorporations in proteins. This leads to increased morphological and physiological phenotypic diversity of high adaptive potential, but the scope of such protein mistranslation is poorly understood due to technical difficulties in detecting and quantifying amino acid misincorporation events in complex protein samples. We have developed and optimized mass spectrometry and bioinformatics pipelines capable of identifying rare amino acid misincorporation events at the proteome level. We have also analyzed the proteomic profile of an engineered C. albicans strain that exhibits high level of leucine misincorporation at protein CUG sites and employed an in vivo quantitative gain-of-function fluorescence reporter system to validate our LC-MS/MS data. C. albicans misincorporates amino acids above the background level at protein sites of diverse codons, particularly at CUG, confirming our previous data on the quantification of leucine incorporation at single CUG sites of recombinant reporter proteins, but increasing misincorporation of Leucine at these sites does not alter the translational fidelity of the other codons. These findings indicate that the C. albicans statistical proteome exceeds prior estimates, suggesting that its highly plastic phenome may also be modulated by environmental factors due to translational ambiguity.
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Affiliation(s)
- Inês Correia
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal.
| | - Carla Oliveira
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Andreia Reis
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Ana Rita Guimarães
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Susana Aveiro
- Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Pedro Domingues
- Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Ana Rita Bezerra
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Rui Vitorino
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Gabriela Moura
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal
| | - Manuel A S Santos
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences (DCM), University of Aveiro, Aveiro, Portugal; Multidisciplinary Institute of Ageing (MIA-Portugal), University of Coimbra, Coimbra, Portugal.
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3
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Akiyama Y, Ivanov P. Oxidative Stress, Transfer RNA Metabolism, and Protein Synthesis. Antioxid Redox Signal 2024; 40:715-735. [PMID: 37767630 PMCID: PMC11001508 DOI: 10.1089/ars.2022.0206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 09/29/2023]
Abstract
Significance: Oxidative stress refers to excessive intracellular levels of reactive oxygen species (ROS) due to an imbalance between ROS production and the antioxidant defense system. Under oxidative stress conditions, cells trigger various stress response pathways to protect themselves, among which repression of messenger RNA (mRNA) translation is one of the key hallmarks promoting cell survival. This regulation process minimizes cellular energy consumption, enabling cells to survive in adverse conditions and to promote recovery from stress-induced damage. Recent Advances: Recent studies suggest that transfer RNAs (tRNAs) play important roles in regulating translation as a part of stress response under adverse conditions. In particular, research relying on high-throughput techniques such as next-generation sequencing and mass spectrometry approaches has given us detailed information on mechanisms such as individual tRNA dynamics and crosstalk among post-transcriptional modifications. Critical Issues: Oxidative stress leads to dynamic tRNA changes, including their localization, cleavage, and alteration of expression profiles and modification patterns. Growing evidence suggests that these changes not only are tightly regulated by stress response mechanisms, but also can directly fine-tune the translation efficiency, which contributes to cell- or tissue-specific response to oxidative stress. Future Directions: In this review, we describe recent advances in the understanding of the dynamic changes of tRNAs caused by oxidative stress. We also highlight the emerging roles of tRNAs in translation regulation under the condition of oxidative stress. In addition, we discuss future perspectives in this research field. Antioxid. Redox Signal. 40, 715-735.
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Affiliation(s)
- Yasutoshi Akiyama
- Laboratory of Oncology, Pharmacy Practice and Sciences, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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4
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Douglas J, Carter CW, Wills PR. HetMM: A Michaelis-Menten model for non-homogeneous enzyme mixtures. iScience 2024; 27:108977. [PMID: 38333698 PMCID: PMC10850774 DOI: 10.1016/j.isci.2024.108977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/21/2023] [Accepted: 01/16/2024] [Indexed: 02/10/2024] Open
Abstract
The Michaelis-Menten model requires its reaction velocities to come from a preparation of homogeneous enzymes, with identical or near-identical catalytic activities. However, this condition is not always met. We introduce a kinetic model that relaxes this requirement, by assuming there are an unknown number of enzyme species drawn from a probability distribution whose standard deviation is estimated. Through simulation studies, we demonstrate the method accurately discriminates between homogeneous and heterogeneous data, even with moderate levels of experimental error. We applied this model to three homogeneous and three heterogeneous biological systems, showing that the standard and heterogeneous models outperform respectively. Lastly, we show that heterogeneity is not readily distinguished from negatively cooperative binding under the Hill model. These two distinct attributes-inequality in catalytic ability and interference between binding sites-yield similar Michaelis-Menten curves that are not readily resolved without further experimentation. Our user-friendly software package allows homogeneity testing and parameter estimation.
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Affiliation(s)
- Jordan Douglas
- Department of Physics, The University of Auckland, Auckland 1010, New Zealand
- Centre for Computational Evolution, The University of Auckland, Auckland 1010, New Zealand
| | - Charles W. Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Peter R. Wills
- Department of Physics, The University of Auckland, Auckland 1010, New Zealand
- Centre for Computational Evolution, The University of Auckland, Auckland 1010, New Zealand
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5
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Baker M, Zhang X, Maciel-Guerra A, Babaarslan K, Dong Y, Wang W, Hu Y, Renney D, Liu L, Li H, Hossain M, Heeb S, Tong Z, Pearcy N, Zhang M, Geng Y, Zhao L, Hao Z, Senin N, Chen J, Peng Z, Li F, Dottorini T. Convergence of resistance and evolutionary responses in Escherichia coli and Salmonella enterica co-inhabiting chicken farms in China. Nat Commun 2024; 15:206. [PMID: 38182559 PMCID: PMC10770378 DOI: 10.1038/s41467-023-44272-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 12/06/2023] [Indexed: 01/07/2024] Open
Abstract
Sharing of genetic elements among different pathogens and commensals inhabiting same hosts and environments has significant implications for antimicrobial resistance (AMR), especially in settings with high antimicrobial exposure. We analysed 661 Escherichia coli and Salmonella enterica isolates collected within and across hosts and environments, in 10 Chinese chicken farms over 2.5 years using data-mining methods. Most isolates within same hosts possessed the same clinically relevant AMR-carrying mobile genetic elements (plasmids: 70.6%, transposons: 78%), which also showed recent common evolution. Supervised machine learning classifiers revealed known and novel AMR-associated mutations and genes underlying resistance to 28 antimicrobials, primarily associated with resistance in E. coli and susceptibility in S. enterica. Many were essential and affected same metabolic processes in both species, albeit with varying degrees of phylogenetic penetration. Multi-modal strategies are crucial to investigate the interplay of mobilome, resistance and metabolism in cohabiting bacteria, especially in ecological settings where community-driven resistance selection occurs.
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Affiliation(s)
- Michelle Baker
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK
| | - Xibin Zhang
- Shandong New Hope Liuhe Group Co. Ltd. and Qingdao Key Laboratory of Animal Feed Safety, Qingdao, Shandong, 266000, P.R. China
| | - Alexandre Maciel-Guerra
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK
| | - Kubra Babaarslan
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK
| | - Yinping Dong
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China
| | - Wei Wang
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China
| | - Yujie Hu
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China
| | - David Renney
- Nimrod Veterinary Products Limited, 2, Wychwood Court, Cotswold Business Village, Moreton-in-Marsh, GL56 0JQ, London, UK
| | - Longhai Liu
- Shandong Kaijia Food Co. Ltd, Weifang, P. R. China
| | - Hui Li
- Luoyang Center for Disease Control and Prevention, No. 9, Zhenghe Road, Luolong District, Luoyang City, Henan Province, Luolong, 471000, P. R. China
| | - Maqsud Hossain
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK
| | - Stephan Heeb
- School of Life Sciences, University of Nottingham, East Drive, Nottingham, Nottinghamshire, NG7 2RD, UK
| | - Zhiqin Tong
- Luoyang Center for Disease Control and Prevention, No. 9, Zhenghe Road, Luolong District, Luoyang City, Henan Province, Luolong, 471000, P. R. China
| | - Nicole Pearcy
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK
- School of Life Sciences, University of Nottingham, East Drive, Nottingham, Nottinghamshire, NG7 2RD, UK
| | - Meimei Zhang
- Liaoning Provincial Center for Disease Control and Prevention, No. 168, Jinfeng Street, Hunnan District, Shenyang City, Liaoning Province, 110072, P. R. China
| | - Yingzhi Geng
- Liaoning Provincial Center for Disease Control and Prevention, No. 168, Jinfeng Street, Hunnan District, Shenyang City, Liaoning Province, 110072, P. R. China
| | - Li Zhao
- Agricultural Biopharmaceutical Laboratory, College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, No. 700 Changcheng Road, Chengyang District, Qingdao City, Shandong Province, 266109, P. R. China
| | - Zhihui Hao
- Chinese Veterinary Medicine Innovation Center, College of Veterinary Medicine, China Agricultural University, Haidian District, Beijing City, 100193, P. R. China
| | - Nicola Senin
- Department of Engineering, University of Perugia, Perugia, I06125, Italy
| | - Junshi Chen
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China
| | - Zixin Peng
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China.
| | - Fengqin Li
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing, 100021, P. R. China.
| | - Tania Dottorini
- School of Veterinary Medicine and Science, University of Nottingham, College Road, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD, UK.
- Centre for Smart Food Research, Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute, University of Nottingham Ningbo China, Ningbo, 315100, P. R. China.
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6
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Jones JD, Franco MK, Smith TJ, Snyder LR, Anders AG, Ruotolo BT, Kennedy RT, Koutmou KS. Methylated guanosine and uridine modifications in S. cerevisiae mRNAs modulate translation elongation. RSC Chem Biol 2023; 4:363-378. [PMID: 37181630 PMCID: PMC10170649 DOI: 10.1039/d2cb00229a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/15/2023] [Indexed: 02/22/2023] Open
Abstract
Chemical modifications to protein encoding messenger RNAs (mRNAs) influence their localization, translation, and stability within cells. Over 15 different types of mRNA modifications have been observed by sequencing and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) approaches. While LC-MS/MS is arguably the most essential tool available for studying analogous protein post-translational modifications, the high-throughput discovery and quantitative characterization of mRNA modifications by LC-MS/MS has been hampered by the difficulty of obtaining sufficient quantities of pure mRNA and limited sensitivities for modified nucleosides. We have overcome these challenges by improving the mRNA purification and LC-MS/MS pipelines. The methodologies we developed result in no detectable non-coding RNA modifications signals in our purified mRNA samples, quantify 50 ribonucleosides in a single analysis, and provide the lowest limit of detection reported for ribonucleoside modification LC-MS/MS analyses. These advancements enabled the detection and quantification of 13 S. cerevisiae mRNA ribonucleoside modifications and reveal the presence of four new S. cerevisiae mRNA modifications at low to moderate levels (1-methyguanosine, N2-methylguanosine, N2,N2-dimethylguanosine, and 5-methyluridine). We identified four enzymes that incorporate these modifications into S. cerevisiae mRNAs (Trm10, Trm11, Trm1, and Trm2, respectively), though our results suggest that guanosine and uridine nucleobases are also non-enzymatically methylated at low levels. Regardless of whether they are incorporated in a programmed manner or as the result of RNA damage, we reasoned that the ribosome will encounter the modifications that we detect in cells. To evaluate this possibility, we used a reconstituted translation system to investigate the consequences of modifications on translation elongation. Our findings demonstrate that the introduction of 1-methyguanosine, N2-methylguanosine and 5-methyluridine into mRNA codons impedes amino acid addition in a position dependent manner. This work expands the repertoire of nucleoside modifications that the ribosome must decode in S. cerevisiae. Additionally, it highlights the challenge of predicting the effect of discrete modified mRNA sites on translation de novo because individual modifications influence translation differently depending on mRNA sequence context.
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Affiliation(s)
- Joshua D Jones
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
| | - Monika K Franco
- Program in Chemical Biology, University of Michigan, 930 N University Ann Arbor MI 48109 USA
| | - Tyler J Smith
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
| | - Laura R Snyder
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
| | - Anna G Anders
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
| | - Robert T Kennedy
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
- Program in Chemical Biology, University of Michigan, 930 N University Ann Arbor MI 48109 USA
| | - Kristin S Koutmou
- Department of Chemistry, University of Michigan, 930 N University Ann Arbor MI 48109 USA +1-734-764-5650
- Program in Chemical Biology, University of Michigan, 930 N University Ann Arbor MI 48109 USA
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7
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Ochoa-Gutiérrez D, Reyes-Torres AM, de la Fuente-Colmenares I, Escobar-Sánchez V, González J, Ortiz-Hernández R, Torres-Ramírez N, Segal-Kischinevzky C. Alternative CUG Codon Usage in the Halotolerant Yeast Debaryomyces hansenii: Gene Expression Profiles Provide New Insights into Ambiguous Translation. J Fungi (Basel) 2022; 8:jof8090970. [PMID: 36135695 PMCID: PMC9502446 DOI: 10.3390/jof8090970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 12/04/2022] Open
Abstract
The halotolerant yeast Debaryomyces hansenii belongs to the CTG-Ser1 clade of fungal species that use the CUG codon to translate as leucine or serine. The ambiguous decoding of the CUG codon is relevant for expanding protein diversity, but little is known about the role of leucine–serine ambiguity in cellular adaptations to extreme environments. Here, we examine sequences and structures of tRNACAG from the CTG-Ser1 clade yeasts, finding that D. hansenii conserves the elements to translate ambiguously. Then, we show that D. hansenii has tolerance to conditions of salinity, acidity, alkalinity, and oxidative stress associated with phenotypic and ultrastructural changes. In these conditions, we found differential expression in both the logarithmic and stationary growth phases of tRNASer, tRNALeu, tRNACAG, LeuRS, and SerRS genes that could be involved in the adaptive process of this yeast. Finally, we compare the proteomic isoelectric points and hydropathy profiles, detecting that the most important variations among the physicochemical characteristics of D. hansenii proteins are in their hydrophobic and hydrophilic interactions with the medium. We propose that the ambiguous translation, i.e., leucylation or serynation, on translation of the CUG-encoded residues, could be linked to adaptation processes in extreme environments.
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Affiliation(s)
- Daniel Ochoa-Gutiérrez
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Anya M. Reyes-Torres
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Ileana de la Fuente-Colmenares
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Viviana Escobar-Sánchez
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - James González
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Rosario Ortiz-Hernández
- Laboratorio de Microscopía Electrónica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Nayeli Torres-Ramírez
- Laboratorio de Microscopía Electrónica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Claudia Segal-Kischinevzky
- Laboratorio de Biología Molecular y Genómica, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad # 3000, Cd. Universitaria, Coyoacán, Mexico City 04510, Mexico
- Correspondence:
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8
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Lyu Z, Ling J. Increase in Ribosomal Fidelity Benefits Salmonella upon Bile Salt Exposure. Genes (Basel) 2022; 13:184. [PMID: 35205229 PMCID: PMC8872077 DOI: 10.3390/genes13020184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023] Open
Abstract
Translational fidelity is maintained by multiple quality control steps in all three domains of life. Increased translational errors (mistranslation) occur due to genetic mutations and external stresses. Severe mistranslation is generally harmful, but moderate levels of mistranslation may be favored under certain conditions. To date, little is known about the link between translational fidelity and host-pathogen interactions. Salmonella enterica can survive in the gall bladder during systemic or chronic infections due to bile resistance. Here we show that increased translational fidelity contributes to the fitness of Salmonella upon bile salt exposure, and the improved fitness depends on an increased level of intracellular adenosine triphosphate (ATP). Our work thus reveals a previously unknown linkage between translational fidelity and bacterial fitness under bile stress.
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Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
- Molecular and Cellular Biology, Bilogical Sciences Graduate Program, The University of Maryland, College Park, MD 20742, USA
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9
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Berg MD, Isaacson JR, Cozma E, Genereaux J, Lajoie P, Villén J, Brandl CJ. Regulating Expression of Mistranslating tRNAs by Readthrough RNA Polymerase II Transcription. ACS Synth Biol 2021; 10:3177-3189. [PMID: 34726901 PMCID: PMC8765249 DOI: 10.1021/acssynbio.1c00461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
Transfer RNA (tRNA)
variants that alter the genetic code increase
protein diversity and have many applications in synthetic biology.
Since the tRNA variants can cause a loss of proteostasis, regulating
their expression is necessary to achieve high levels of novel protein.
Mechanisms to positively regulate transcription with exogenous activator
proteins like those often used to regulate RNA polymerase II (RNAP
II)-transcribed genes are not applicable to tRNAs as their expression
by RNA polymerase III requires elements internal to the tRNA. Here,
we show that tRNA expression is repressed by overlapping transcription
from an adjacent RNAP II promoter. Regulating the expression of the
RNAP II promoter allows inverse regulation of the tRNA. Placing either
Gal4- or TetR–VP16-activated promoters downstream of a mistranslating
tRNASer variant that misincorporates serine at proline
codons in Saccharomyces cerevisiae allows
mistranslation at a level not otherwise possible because of the toxicity
of the unregulated tRNA. Using this inducible tRNA system, we explore
the proteotoxic effects of mistranslation on yeast cells. High levels
of mistranslation cause cells to arrest in the G1 phase. These cells
are impermeable to propidium iodide, yet growth is not restored upon
repressing tRNA expression. High levels of mistranslation increase
cell size and alter cell morphology. This regulatable tRNA expression
system can be applied to study how native tRNAs and tRNA variants
affect the proteome and other biological processes. Variations of
this inducible tRNA system should be applicable to other eukaryotic
cell types.
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Affiliation(s)
- Matthew D. Berg
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Joshua R. Isaacson
- Department of Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ecaterina Cozma
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Patrick Lajoie
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Judit Villén
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Christopher J. Brandl
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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10
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Santamaría-Gómez J, Rubio MÁ, López-Igual R, Romero-Losada AB, Delgado-Chaves FM, Bru-Martínez R, Romero-Campero FJ, Herrero A, Ibba M, Ochoa de Alda JAG, Luque I. Role of a cryptic tRNA gene operon in survival under translational stress. Nucleic Acids Res 2021; 49:8757-8776. [PMID: 34379789 PMCID: PMC8421152 DOI: 10.1093/nar/gkab661] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/12/2021] [Accepted: 07/22/2021] [Indexed: 01/08/2023] Open
Abstract
As compared to eukaryotes, bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs. Although in most bacterial phyla tRNA genes are dispersed in the genome, many species from distinct phyla also show genes forming arrays. Here, we show that two types of arrays with distinct evolutionary origins exist. This work focuses on long tRNA gene arrays (L-arrays) that encompass up to 43 genes, which disseminate by horizontal gene transfer and contribute supernumerary tRNA genes to the host. Although in the few cases previously studied these arrays were reported to be poorly transcribed, here we show that the L-array of the model cyanobacterium Anabaena sp. PCC 7120, encoding 23 functional tRNAs, is largely induced upon impairment of the translation machinery. The cellular response to this challenge involves a global reprogramming of the transcriptome in two phases. tRNAs encoded in the array are induced in the second phase of the response, directly contributing to cell survival. Results presented here show that in some bacteria the tRNA gene set may be partitioned between a housekeeping subset, which constantly sustains translation, and an inducible subset that is generally silent but can provide functionality under particular conditions.
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Affiliation(s)
- Javier Santamaría-Gómez
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain
| | - Miguel Ángel Rubio
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain.,Center for RNA Biology, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA
| | - Rocío López-Igual
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain
| | - Ana B Romero-Losada
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain.,Department of Computer Science and Artificial Intelligence, Universidad de Sevilla, Seville E-41012, Spain
| | - Fernando M Delgado-Chaves
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain
| | - Roque Bru-Martínez
- Department of Agrochemistry and Biochemistry, Faculty of Science, University of Alicante, Alicante E- 03690, Spain
| | - Francisco J Romero-Campero
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain.,Department of Computer Science and Artificial Intelligence, Universidad de Sevilla, Seville E-41012, Spain
| | - Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain
| | - Michael Ibba
- Center for RNA Biology, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA.,Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA 92866, USA
| | - Jesús A G Ochoa de Alda
- Didáctica de las Ciencias Experimentales, Facultad de Formación del Profesorado, Universidad de Extremadura, Cáceres E-10003, Spain
| | - Ignacio Luque
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Seville E-41092, Spain
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11
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Nombela P, Miguel-López B, Blanco S. The role of m 6A, m 5C and Ψ RNA modifications in cancer: Novel therapeutic opportunities. Mol Cancer 2021; 20:18. [PMID: 33461542 PMCID: PMC7812662 DOI: 10.1186/s12943-020-01263-w] [Citation(s) in RCA: 259] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
RNA modifications have recently emerged as critical posttranscriptional regulators of gene expression programmes. Significant advances have been made in understanding the functional role of RNA modifications in regulating coding and non-coding RNA processing and function, which in turn thoroughly shape distinct gene expression programmes. They affect diverse biological processes, and the correct deposition of many of these modifications is required for normal development. Alterations of their deposition are implicated in several diseases, including cancer. In this Review, we focus on the occurrence of N6-methyladenosine (m6A), 5-methylcytosine (m5C) and pseudouridine (Ψ) in coding and non-coding RNAs and describe their physiopathological role in cancer. We will highlight the latest insights into the mechanisms of how these posttranscriptional modifications influence tumour development, maintenance, and progression. Finally, we will summarize the latest advances on the development of small molecule inhibitors that target specific writers or erasers to rewind the epitranscriptome of a cancer cell and their therapeutic potential.
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Affiliation(s)
- Paz Nombela
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - University of Salamanca, 37007, Salamanca, Spain
| | - Borja Miguel-López
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - University of Salamanca, 37007, Salamanca, Spain
| | - Sandra Blanco
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - University of Salamanca, 37007, Salamanca, Spain. .,Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007, Salamanca, Spain.
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12
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Vihinen M. Functional effects of protein variants. Biochimie 2020; 180:104-120. [PMID: 33164889 DOI: 10.1016/j.biochi.2020.10.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022]
Abstract
Genetic and other variations frequently affect protein functions. Scientific articles can contain confusing descriptions about which function or property is affected, and in many cases the statements are pure speculation without any experimental evidence. To clarify functional effects of protein variations of genetic or non-genetic origin, a systematic conceptualisation and framework are introduced. This framework describes protein functional effects on abundance, activity, specificity and affinity, along with countermeasures, which allow cells, tissues and organisms to tolerate, avoid, repair, attenuate or resist (TARAR) the effects. Effects on abundance discussed include gene dosage, restricted expression, mis-localisation and degradation. Enzymopathies, effects on kinetics, allostery and regulation of protein activity are subtopics for the effects of variants on activity. Variation outcomes on specificity and affinity comprise promiscuity, specificity, affinity and moonlighting. TARAR mechanisms redress variations with active and passive processes including chaperones, redundancy, robustness, canalisation and metabolic and signalling rewiring. A framework for pragmatic protein function analysis and presentation is introduced. All of the mechanisms and effects are described along with representative examples, most often in relation to diseases. In addition, protein function is discussed from evolutionary point of view. Application of the presented framework facilitates unambiguous, detailed and specific description of functional effects and their systematic study.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, BMC B13, Lund University, SE-22 184, Lund, Sweden.
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13
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Han NC, Kelly P, Ibba M. Translational quality control and reprogramming during stress adaptation. Exp Cell Res 2020; 394:112161. [PMID: 32619498 DOI: 10.1016/j.yexcr.2020.112161] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/18/2022]
Abstract
Organisms encounter stress throughout their lives, and therefore require the ability to respond rapidly to environmental changes. Although transcriptional responses are crucial for controlling changes in gene expression, regulation at the translational level often allows for a faster response at the protein levels which permits immediate adaptation. The fidelity and robustness of protein synthesis are actively regulated under stress. For example, mistranslation can be beneficial to cells upon environmental changes and also alters cellular stress responses. Additionally, stress modulates both global and selective translational regulation through mechanisms including the change of aminoacyl-tRNA activity, tRNA pool reprogramming and ribosome heterogeneity. In this review, we draw on studies from both the prokaryotic and eukaryotic systems to discuss current findings of cellular adaptation at the level of translation, specifically translational fidelity and activity changes in response to a wide array of environmental stressors including oxidative stress, nutrient depletion, temperature variation, antibiotics and host colonization.
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Affiliation(s)
- Nien-Ching Han
- Department of Microbiology, The Ohio State University, Columbus, OH, 43220, USA
| | - Paul Kelly
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH, 43220, USA
| | - Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, OH, 43220, USA.
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14
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Jones JD, Monroe J, Koutmou KS. A molecular-level perspective on the frequency, distribution, and consequences of messenger RNA modifications. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1586. [PMID: 31960607 PMCID: PMC8243748 DOI: 10.1002/wrna.1586] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/21/2019] [Accepted: 01/04/2020] [Indexed: 01/16/2023]
Abstract
Cells use chemical modifications to alter the sterics, charge, and conformations of large biomolecules, modulating their biogenesis, function, and stability. Until recently post-transcriptional RNA modifications were thought to be largely limited to nonprotein coding RNA species. However, this dogma has rapidly transformed with the discovery of a host of modifications in protein coding messenger RNAs (mRNAs). Recent advancements in genome-wide sequencing technologies have enabled the identification of mRNA modifications as a potential new frontier in gene regulation-leading to the development of the epitranscriptome field. As a result, there has been a flurry of multiple groundbreaking discoveries, including new modifications, nucleoside modifying enzymes ("writers" and "erasers"), and RNA binding proteins that recognize chemical modifications ("readers"). These discoveries opened the door to understanding how post-transcriptional mRNA modifications can modulate the mRNA lifecycle, and established a link between the epitranscriptome and human health and disease. Despite a rapidly growing recognition of their importance, fundamental questions regarding the identity, prevalence, and functional consequences of mRNA modifications remain to be answered. Here, we highlight quantitative studies that characterize mRNA modification abundance, frequency, and interactions with cellular machinery. As the field progresses, we see a need for the further integration of quantitative and reductionist approaches to complement transcriptome wide studies in order to establish a molecular-level framework for understanding the consequences of mRNA chemical modifications on biological processes. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Joshua D. Jones
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Jeremy Monroe
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Kristin S. Koutmou
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan
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15
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Premature termination codon readthrough in Drosophila varies in a developmental and tissue-specific manner. Sci Rep 2020; 10:8485. [PMID: 32444687 PMCID: PMC7244557 DOI: 10.1038/s41598-020-65348-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/31/2020] [Indexed: 12/29/2022] Open
Abstract
Despite their essential function in terminating translation, readthrough of stop codons occurs more frequently than previously supposed. However, little is known about the regulation of stop codon readthrough by anatomical site and over the life cycle of animals. Here, we developed a set of reporters to measure readthrough in Drosophila melanogaster. A focused RNAi screen in whole animals identified upf1 as a mediator of readthrough, suggesting that the stop codons in the reporters were recognized as premature termination codons (PTCs). We found readthrough rates of PTCs varied significantly throughout the life cycle of flies, being highest in older adult flies. Furthermore, readthrough rates varied dramatically by tissue and, intriguingly, were highest in fly brains, specifically neurons and not glia. This was not due to differences in reporter abundance or nonsense-mediated mRNA decay (NMD) surveillance between these tissues. Readthrough rates also varied within neurons, with cholinergic neurons having highest readthrough compared with lowest readthrough rates in dopaminergic neurons. Overall, our data reveal temporal and spatial variation of PTC-mediated readthrough in animals, and suggest that readthrough may be a potential rescue mechanism for PTC-harboring transcripts when the NMD surveillance pathway is inhibited.
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16
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Weitzel CS, Li L, Zhang C, Eilts KK, Bretz NM, Gatten AL, Whitaker RJ, Martinis SA. Duplication of leucyl-tRNA synthetase in an archaeal extremophile may play a role in adaptation to variable environmental conditions. J Biol Chem 2020; 295:4563-4576. [PMID: 32102848 DOI: 10.1074/jbc.ra118.006481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 02/25/2020] [Indexed: 12/23/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are ancient enzymes that play a fundamental role in protein synthesis. They catalyze the esterification of specific amino acids to the 3'-end of their cognate tRNAs and therefore play a pivotal role in protein synthesis. Although previous studies suggest that aaRS-dependent errors in protein synthesis can be beneficial to some microbial species, evidence that reduced aaRS fidelity can be adaptive is limited. Using bioinformatics analyses, we identified two distinct leucyl-tRNA synthetase (LeuRS) genes within all genomes of the archaeal family Sulfolobaceae. Remarkably, one copy, designated LeuRS-I, had key amino acid substitutions within its editing domain that would be expected to disrupt hydrolytic editing of mischarged tRNALeu and to result in variation within the proteome of these extremophiles. We found that another copy, LeuRS-F, contains canonical active sites for aminoacylation and editing. Biochemical and genetic analyses of the paralogs within Sulfolobus islandicus supported the hypothesis that LeuRS-F, but not LeuRS-I, functions as an essential tRNA synthetase that accurately charges leucine to tRNALeu for protein translation. Although LeuRS-I was not essential, its expression clearly supported optimal S. islandicus growth. We conclude that LeuRS-I may have evolved to confer a selective advantage under the extreme and fluctuating environmental conditions characteristic of the volcanic hot springs in which these archaeal extremophiles reside.
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Affiliation(s)
| | - Li Li
- Department of Biochemistry, University of Illinois, Urbana, Illinois 61801.,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, Illinois 61801
| | - Changyi Zhang
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - Kristen K Eilts
- Department of Chemistry, Illinois State University, Normal, Illinois 61761
| | - Nicholas M Bretz
- Department of Chemistry, Illinois State University, Normal, Illinois 61761
| | - Alex L Gatten
- Department of Biochemistry, University of Illinois, Urbana, Illinois 61801
| | - Rachel J Whitaker
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - Susan A Martinis
- Department of Biochemistry, University of Illinois, Urbana, Illinois 61801.,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, Illinois 61801
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17
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Berg MD, Zhu Y, Genereaux J, Ruiz BY, Rodriguez-Mias RA, Allan T, Bahcheli A, Villén J, Brandl CJ. Modulating Mistranslation Potential of tRNA Ser in Saccharomyces cerevisiae. Genetics 2019; 213:849-863. [PMID: 31484688 PMCID: PMC6827378 DOI: 10.1534/genetics.119.302525] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/01/2019] [Indexed: 12/15/2022] Open
Abstract
Transfer RNAs (tRNAs) read the genetic code, translating nucleic acid sequence into protein. For tRNASer the anticodon does not specify its aminoacylation. For this reason, mutations in the tRNASer anticodon can result in amino acid substitutions, a process called mistranslation. Previously, we found that tRNASer with a proline anticodon was lethal to cells. However, by incorporating secondary mutations into the tRNA, mistranslation was dampened to a nonlethal level. The goal of this work was to identify second-site substitutions in tRNASer that modulate mistranslation to different levels. Targeted changes to putative identity elements led to total loss of tRNA function or significantly impaired cell growth. However, through genetic selection, we identified 22 substitutions that allow nontoxic mistranslation. These secondary mutations are primarily in single-stranded regions or substitute G:U base pairs for Watson-Crick pairs. Many of the variants are more toxic at low temperature and upon impairing the rapid tRNA decay pathway. We suggest that the majority of the secondary mutations affect the stability of the tRNA in cells. The temperature sensitivity of the tRNAs allows conditional mistranslation. Proteomic analysis demonstrated that tRNASer variants mistranslate to different extents with diminished growth correlating with increased mistranslation. When combined with a secondary mutation, other anticodon substitutions allow serine mistranslation at additional nonserine codons. These mistranslating tRNAs have applications in synthetic biology, by creating "statistical proteins," which may display a wider range of activities or substrate specificities than the homogenous form.
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Affiliation(s)
- Matthew D Berg
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Yanrui Zhu
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Bianca Y Ruiz
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195
| | | | - Tyler Allan
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Alexander Bahcheli
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Judit Villén
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195
| | - Christopher J Brandl
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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18
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Abstract
Chemical modifications of RNAs have long been established as key modulators of nonprotein-coding RNA structure and function in cells. There is a growing appreciation that messenger RNA (mRNA) sequences responsible for directing protein synthesis can also be posttranscriptionally modified. The enzymatic incorporation of mRNA modifications has many potential outcomes, including changing mRNA stability, protein recruitment, and translation. We tested how one of the most common modifications present in mRNA coding regions, pseudouridine (Ψ), impacts protein synthesis using a fully reconstituted bacterial translation system and human cells. Our work reveals that replacing a single uridine nucleotide with Ψ in an mRNA codon impedes amino acid addition and EF-Tu GTPase activation. A crystal structure of the Thermus thermophilus 70S ribosome with a tRNAPhe bound to a ΨUU codon in the A site supports these findings. We also find that the presence of Ψ can promote the low-level synthesis of multiple peptide products from a single mRNA sequence in the reconstituted translation system as well as human cells, and increases the rate of near-cognate Val-tRNAVal reacting on a ΨUU codon. The vast majority of Ψ moieties in mRNAs are found in coding regions, and our study suggests that one consequence of the ribosome encountering Ψ can be to modestly alter both translation speed and mRNA decoding.
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19
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Evans CR, Fan Y, Ling J. Increased mistranslation protects E. coli from protein misfolding stress due to activation of a RpoS-dependent heat shock response. FEBS Lett 2019; 593:3220-3227. [PMID: 31419308 PMCID: PMC6878130 DOI: 10.1002/1873-3468.13578] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/02/2019] [Accepted: 08/08/2019] [Indexed: 01/01/2023]
Abstract
The misincorporation of an incorrect amino acid into a polypeptide during protein synthesis is considered a detrimental phenomenon. A mistranslated protein is often misfolded and degraded or nonfunctional and results in an increased cost to quality control machinery. Despite these costs, errors during protein synthesis are common in bacteria. Here, we report that mistranslation in Escherichia coli increase the protein level of the heat shock sigma factor RpoH and protect cells against heat stress. Surprisingly, this increase in RpoH due to mistranslation is dependent on the presence of the general stress response sigma factor RpoS. This report provides evidence for a protective function of mistranslation and suggests a novel regulatory role of RpoS in the heat shock response.
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Affiliation(s)
- Christopher R Evans
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Yongqiang Fan
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
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20
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Advani VM, Ivanov P. Translational Control under Stress: Reshaping the Translatome. Bioessays 2019; 41:e1900009. [PMID: 31026340 PMCID: PMC6541386 DOI: 10.1002/bies.201900009] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/06/2019] [Indexed: 01/01/2023]
Abstract
Adequate reprogramming of cellular metabolism in response to stresses or suboptimal growth conditions involves a myriad of coordinated changes that serve to promote cell survival. As protein synthesis is an energetically expensive process, its regulation under stress is of critical importance. Reprogramming of messenger RNA (mRNA) translation involves well-understood stress-activated kinases that target components of translation initiation machinery, resulting in the robust inhibition of general translation and promotion of the translation of stress-responsive proteins. Translational arrest of mRNAs also results in the accumulation of transcripts in cytoplasmic foci called stress granules. Recent studies focus on the key roles of transfer RNA (tRNA) in stress-induced translational reprogramming. These include stress-specific regulation of tRNA pools, codon-biased translation influenced by tRNA modifications, tRNA miscoding, and tRNA cleavage. In combination, signal transduction pathways and tRNA metabolism changes regulate translation during stress, resulting in adaptation and cell survival. This review examines molecular mechanisms that regulate protein synthesis in response to stress.
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Affiliation(s)
- Vivek M. Advani
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- The Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts, United States of America
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21
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Zimmerman SM, Kon Y, Hauke AC, Ruiz BY, Fields S, Phizicky EM. Conditional accumulation of toxic tRNAs to cause amino acid misincorporation. Nucleic Acids Res 2018; 46:7831-7843. [PMID: 30007351 PMCID: PMC6125640 DOI: 10.1093/nar/gky623] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 06/22/2018] [Accepted: 07/01/2018] [Indexed: 12/16/2022] Open
Abstract
To develop a system for conditional amino acid misincorporation, we engineered tRNAs in the yeast Saccharomyces cerevisiae to be substrates of the rapid tRNA decay (RTD) pathway, such that they accumulate when RTD is turned off. We used this system to test the effects on growth of a library of tRNASer variants with all possible anticodons, and show that many are lethal when RTD is inhibited and the tRNA accumulates. Using mass spectrometry, we measured serine misincorporation in yeast containing each of six tRNA variants, and for five of them identified hundreds of peptides with serine substitutions at the targeted amino acid sites. Unexpectedly, we found that there is not a simple correlation between toxicity and the level of serine misincorporation; in particular, high levels of serine misincorporation can occur at cysteine residues without obvious growth defects. We also showed that toxic tRNAs can be used as a tool to identify sequence variants that reduce tRNA function. Finally, we generalized this method to another tRNA species, and generated conditionally toxic tRNATyr variants in a similar manner. This method should facilitate the study of tRNA biology and provide a tool to probe the effects of amino acid misincorporation on cellular physiology.
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Affiliation(s)
| | - Yoshiko Kon
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Alayna C Hauke
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Bianca Y Ruiz
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Stanley Fields
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, NY 14642, USA
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22
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Koh CS, Sarin LP. Transfer RNA modification and infection – Implications for pathogenicity and host responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:419-432. [DOI: 10.1016/j.bbagrm.2018.01.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/04/2018] [Accepted: 01/19/2018] [Indexed: 12/19/2022]
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23
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Evans CR, Ling J. Visualizing translational errors: one cell at a time. Curr Genet 2017; 64:551-554. [PMID: 29159424 DOI: 10.1007/s00294-017-0784-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 01/04/2023]
Abstract
Physiological heterogeneity among single cells with identical genetic information has been observed in a large number of bacterial phenotypes, including growth, stress responses, cell size, and antibiotic tolerance. Despite the widespread observation of this phenomenon in bacterial populations, not much is known about the molecular mechanisms behind phenotypic heterogeneity. Currently, our understanding is primarily limited to transcriptional profile of single cells using fluorescence reporters. Although the development of these tools has been extremely informative, it cannot fully explain the heterogeneity seen in populations. In a recent publication, Fan et al. have developed a dual-fluorescent reporter system that is capable of quantitatively measuring translational fidelity in single cells. It is shown that translational fidelity is heterogeneous and affects the growth characteristics of single cells. The development of tools for analysis of molecular heterogeneity downstream of transcription may play an important role in advancing our understanding of the physiology of bacterial populations.
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Affiliation(s)
- Christopher R Evans
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX, 77030, USA.,Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX, 77030, USA. .,Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.
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24
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Desai R, Kim K, Büchsenschütz HC, Chen AW, Bi Y, Mann MR, Turk MA, Chung CZ, Heinemann IU. Minimal requirements for reverse polymerization and tRNA repair by tRNA His guanylyltransferase. RNA Biol 2017; 15:614-622. [PMID: 28901837 DOI: 10.1080/15476286.2017.1372076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
tRNAHis guanylyltransferase (Thg1) has unique reverse (3'-5') polymerase activity occurring in all three domains of life. Most eukaryotic Thg1 homologs are essential genes involved in tRNAHis maturation. These enzymes normally catalyze a single 5' guanylation of tRNAHis lacking the essential G-1 identity element required for aminoacylation. Recent studies suggest that archaeal type Thg1, which includes most archaeal and bacterial Thg1 enzymes is phylogenetically distant from eukaryotic Thg1. Thg1 is evolutionarily related to canonical 5'-3' forward polymerases but catalyzes reverse 3'-5'polymerization. Similar to its forward polymerase counterparts, Thg1 encodes the conserved catalytic palm domain and fingers domain. Here we investigate the minimal requirements for reverse polymerization. We show that the naturally occurring minimal Thg1 enzyme from Ignicoccus hospitalis (IhThg1), which lacks parts of the conserved fingers domain, is catalytically active. And adds all four natural nucleotides to RNA substrates, we further show that the entire fingers domain of Methanosarcina acetivorans Thg1 and Pyrobaculum aerophilum Thg1 (PaThg1) is dispensable for enzymatic activity. In addition, we identified residues in yeast Thg1 that play a part in preventing extended polymerization. Mutation of these residues with alanine resulted in extended reverse polymerization. PaThg1 was found to catalyze extended, template dependent tRNA repair, adding up to 13 nucleotides to a truncated tRNAHis substrate. Sequencing results suggest that PaThg1 fully restored the near correct sequence of the D- and acceptor stem, but also produced incompletely and incorrectly repaired tRNA products. This research forms the basis for future engineering efforts towards a high fidelity, template dependent reverse polymerase.
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Affiliation(s)
- Riddhi Desai
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Kunmo Kim
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | | | - Allan W Chen
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Yumin Bi
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Mitchell R Mann
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Matthew A Turk
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Christina Z Chung
- a Department of Biochemistry , The University of Western Ontario , London , Canada
| | - Ilka U Heinemann
- a Department of Biochemistry , The University of Western Ontario , London , Canada
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25
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The emerging complexity of the tRNA world: mammalian tRNAs beyond protein synthesis. Nat Rev Mol Cell Biol 2017; 19:45-58. [PMID: 28875994 DOI: 10.1038/nrm.2017.77] [Citation(s) in RCA: 277] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The discovery of the genetic code and tRNAs as decoders of the code transformed life science. However, after establishing the role of tRNAs in protein synthesis, the field moved to other parts of the RNA world. Now, tRNA research is blooming again, with demonstration of the involvement of tRNAs in various other pathways beyond translation and in adapting translation to environmental cues. These roles are linked to the presence of tRNA sequence variants known as isoacceptors and isodecoders, various tRNA base modifications, the versatility of protein binding partners and tRNA fragmentation events, all of which collectively create an incalculable complexity. This complexity provides a vast repertoire of tRNA species that can serve various functions in cellular homeostasis and in adaptation of cellular functions to changing environments, and it likely arose from the fundamental role of RNAs in early evolution.
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26
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Translational fidelity and mistranslation in the cellular response to stress. Nat Microbiol 2017; 2:17117. [PMID: 28836574 DOI: 10.1038/nmicrobiol.2017.117] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/20/2017] [Indexed: 11/08/2022]
Abstract
Faithful translation of mRNA into the corresponding polypeptide is a complex multistep process, requiring accurate amino acid selection, transfer RNA (tRNA) charging and mRNA decoding on the ribosome. Key players in this process are aminoacyl-tRNA synthetases (aaRSs), which not only catalyse the attachment of cognate amino acids to their respective tRNAs, but also selectively hydrolyse incorrectly activated non-cognate amino acids and/or misaminoacylated tRNAs. This aaRS proofreading provides quality control checkpoints that exclude non-cognate amino acids during translation, and in so doing helps to prevent the formation of an aberrant proteome. However, despite the intrinsic need for high accuracy during translation, and the widespread evolutionary conservation of aaRS proofreading pathways, requirements for translation quality control vary depending on cellular physiology and changes in growth conditions, and translation errors are not always detrimental. Recent work has demonstrated that mistranslation can also be beneficial to cells, and some organisms have selected for a higher degree of mistranslation than others. The aims of this Review Article are to summarize the known mechanisms of protein translational fidelity and explore the diversity and impact of mistranslation events as a potentially beneficial response to environmental and cellular stress.
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27
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Hoffman KS, Berg MD, Shilton BH, Brandl CJ, O'Donoghue P. Genetic selection for mistranslation rescues a defective co-chaperone in yeast. Nucleic Acids Res 2017; 45:3407-3421. [PMID: 27899648 PMCID: PMC5389508 DOI: 10.1093/nar/gkw1021] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022] Open
Abstract
Despite the general requirement for translation fidelity, mistranslation can be an adaptive response. We selected spontaneous second site mutations that suppress the stress sensitivity caused by a Saccharomyces cerevisiae tti2 allele with a Leu to Pro mutation at residue 187, identifying a single nucleotide mutation at the same position (C70U) in four tRNAProUGG genes. Linkage analysis and suppression by SUF9G3:U70 expressed from a centromeric plasmid confirmed the causative nature of the suppressor mutation. Since the mutation incorporates the G3:U70 identity element for alanyl-tRNA synthetase into tRNAPro, we hypothesized that suppression results from mistranslation of Pro187 in Tti2L187P as Ala. A strain expressing Tti2L187A was not stress sensitive. In vitro, tRNAProUGG (C70U) was mis-aminoacylated with alanine by alanyl–tRNA synthetase, but was not a substrate for prolyl–tRNA synthetase. Mass spectrometry from protein expressed in vivo and a novel GFP reporter for mistranslation confirmed substitution of alanine for proline at a rate of ∼6%. Mistranslating cells expressing SUF9G3:U70 induce a partial heat shock response but grow nearly identically to wild-type. Introducing the same G3:U70 mutation in SUF2 (tRNAProAGG) suppressed a second tti2 allele (tti2L50P). We have thus identified a strategy that allows mistranslation to suppress deleterious missense Pro mutations in Tti2.
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Affiliation(s)
- Kyle S Hoffman
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Matthew D Berg
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Brian H Shilton
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Christopher J Brandl
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada.,Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
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28
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Schwartz MH, Pan T. tRNA Misacylation with Methionine in the Mouse Gut Microbiome in Situ. MICROBIAL ECOLOGY 2017; 74:10-14. [PMID: 28070678 PMCID: PMC5466836 DOI: 10.1007/s00248-016-0928-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 12/28/2016] [Indexed: 06/06/2023]
Abstract
Global protein mistranslation with methionine has been shown to be a conserved biological process that affords distinct functional advantages in all three domains of life. In all instances, methionine mistranslation occurs through a regulated process where low-fidelity forms of methionyl-tRNA synthetase are conditionally induced to mischarge non-methionyl-tRNAs with methionine followed by the utilization of the misacylated tRNAs in translation. In mammals, methionine mistranslation contributes to oxidative stress response; in the hyperthermophilic archaeon Aeropyrum pernix, methionine mistranslation produces proteins that are better adapted to low temperature growth; in E. coli, methionine mistranslation increases resistance to antibiotics and chemical stressors. The phenotypic benefits conferred by tRNA mismethionylation suggest that it should be a widespread adaptational mechanism in diverse bacterial lineages, yet this response has only been described in E. coli. Furthermore, previous microbial investigations on this response have been confined to axenic laboratory cultures. It was unknown whether tRNA mismethionylation was relevant in a natural microbial habitat. Here we show that four abundant gut microbiotal genera belonging to the Firmicutes and Bacteroidetes phyla perform constitutive tRNA misacylation with methionine in the mouse cecum in situ. These results reveal the ubiquity of the tRNA mismethionylation process among bacteria and implicate the potential importance of this response for subsistence and adaptation in natural habitats.
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Affiliation(s)
- Michael H Schwartz
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Committee on Microbiology, University of Chicago, Chicago, IL, 60637, USA.
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Committee on Microbiology, University of Chicago, Chicago, IL, 60637, USA.
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29
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Mistranslation: from adaptations to applications. Biochim Biophys Acta Gen Subj 2017; 1861:3070-3080. [PMID: 28153753 DOI: 10.1016/j.bbagen.2017.01.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND The conservation of the genetic code indicates that there was a single origin, but like all genetic material, the cell's interpretation of the code is subject to evolutionary pressure. Single nucleotide variations in tRNA sequences can modulate codon assignments by altering codon-anticodon pairing or tRNA charging. Either can increase translation errors and even change the code. The frozen accident hypothesis argued that changes to the code would destabilize the proteome and reduce fitness. In studies of model organisms, mistranslation often acts as an adaptive response. These studies reveal evolutionary conserved mechanisms to maintain proteostasis even during high rates of mistranslation. SCOPE OF REVIEW This review discusses the evolutionary basis of altered genetic codes, how mistranslation is identified, and how deviations to the genetic code are exploited. We revisit early discoveries of genetic code deviations and provide examples of adaptive mistranslation events in nature. Lastly, we highlight innovations in synthetic biology to expand the genetic code. MAJOR CONCLUSIONS The genetic code is still evolving. Mistranslation increases proteomic diversity that enables cells to survive stress conditions or suppress a deleterious allele. Genetic code variants have been identified by genome and metagenome sequence analyses, suppressor genetics, and biochemical characterization. GENERAL SIGNIFICANCE Understanding the mechanisms of translation and genetic code deviations enables the design of new codes to produce novel proteins. Engineering the translation machinery and expanding the genetic code to incorporate non-canonical amino acids are valuable tools in synthetic biology that are impacting biomedical research. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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30
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Rewiring protein synthesis: From natural to synthetic amino acids. Biochim Biophys Acta Gen Subj 2017; 1861:3024-3029. [PMID: 28095316 DOI: 10.1016/j.bbagen.2017.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/21/2022]
Abstract
BACKGROUND The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. SCOPE OF REVIEW This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome. We will discuss evolution and engineering of such components that allow incorporation of natural and synthetic amino acids at positions that deviate from the standard genetic code. MAJOR CONCLUSIONS The protein synthesis machinery is highly selective, yet not fixed, for the correct amino acids that match the mRNA codons. Ambiguous translation of a codon with multiple amino acids or complete reassignment of a codon with a synthetic amino acid diversifies the proteome. GENERAL SIGNIFICANCE Expanding the genetic code with synthetic amino acids through rewiring protein synthesis has broad applications in synthetic biology and chemical biology. Biochemical, structural, and genetic studies of the translational quality control mechanisms are not only crucial to understand the physiological role of translational fidelity and evolution of the genetic code, but also enable us to better design biological parts to expand the proteomes of synthetic organisms. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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31
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Schwartz MH, Pan T. Function and origin of mistranslation in distinct cellular contexts. Crit Rev Biochem Mol Biol 2017; 52:205-219. [PMID: 28075177 DOI: 10.1080/10409238.2016.1274284] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mistranslation describes errors during protein synthesis that prevent the amino acid sequences specified in the genetic code from being reflected within proteins. For a long time, mistranslation has largely been considered an aberrant cellular process that cells actively avoid at all times. However, recent evidence has demonstrated that cells from all three domains of life not only tolerate certain levels and forms of mistranslation, but actively induce mistranslation under certain circumstances. To this end, dedicated biological mechanisms have recently been found to reduce translational fidelity, which indicates that mistranslation is not exclusively an erroneous process and can even benefit cells in particular cellular contexts. There currently exists a spectrum of mistranslational processes that differ not only in their origins, but also in their molecular and cellular effects. These findings suggest that the optimal degree of translational fidelity largely depends on a specific cellular context. This review aims to conceptualize the basis and functional consequence of the diverse types of mistranslation that have been described so far.
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Affiliation(s)
- Michael H Schwartz
- a Department of Biochemistry and Molecular Biology , University of Chicago, Chicago , IL , USA
| | - Tao Pan
- a Department of Biochemistry and Molecular Biology , University of Chicago, Chicago , IL , USA
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32
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Sun L, Gomes AC, He W, Zhou H, Wang X, Pan DW, Schimmel P, Pan T, Yang XL. Evolutionary Gain of Alanine Mischarging to Noncognate tRNAs with a G4:U69 Base Pair. J Am Chem Soc 2016; 138:12948-12955. [PMID: 27622773 DOI: 10.1021/jacs.6b07121] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fidelity of translation, which is predominately dictated by the accuracy of aminoacyl-tRNA synthetases in pairing amino acids with correct tRNAs, is of central importance in biology. Yet, deliberate modifications of translational fidelity can be beneficial. Here we found human and not E. coli AlaRS has an intrinsic capacity for mispairing alanine onto nonalanyl-tRNAs including tRNACys. Consistently, a cysteine-to-alanine substitution was found in a reporter protein expressed in human cells. All human AlaRS-mischarged tRNAs have a G4:U69 base pair in the acceptor stem. The base pair is required for the mischarging. By solving the crystal structure of human AlaRS and comparing it to that of E. coli AlaRS, we identified a key sequence divergence between eukaryotes and bacteria that influences mischarging. Thus, the expanded tRNA specificity of AlaRS appears to be an evolutionary gain-of-function to provide posttranscriptional alanine substitutions in eukaryotic proteins for potential regulations.
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Affiliation(s)
- Litao Sun
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Ana Cristina Gomes
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Weiwei He
- Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Huihao Zhou
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Xiaoyun Wang
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - David W Pan
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Paul Schimmel
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago , Chicago, Illinois 60637, United States
| | - Xiang-Lei Yang
- Department of Cell and Molecular Biology, The Scripps Research Institute , La Jolla, California 92037, United States.,Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92037, United States
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33
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Schwartz MH, Waldbauer JR, Zhang L, Pan T. Global tRNA misacylation induced by anaerobiosis and antibiotic exposure broadly increases stress resistance in Escherichia coli. Nucleic Acids Res 2016; 44:10292-10303. [PMID: 27672035 PMCID: PMC5137444 DOI: 10.1093/nar/gkw856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/14/2016] [Accepted: 09/16/2016] [Indexed: 12/22/2022] Open
Abstract
High translational fidelity is commonly considered a requirement for optimal cellular health and protein function. However, recent findings have shown that inducible mistranslation specifically with methionine engendered at the tRNA charging level occurs in mammalian cells, yeast and archaea, yet it was unknown whether bacteria were capable of mounting a similar response. Here, we demonstrate that Escherichia coli misacylates non-methionyl-tRNAs with methionine in response to anaerobiosis and antibiotic exposure via the methionyl–tRNA synthetase (MetRS). Two MetRS succinyl-lysine modifications independently confer high tRNA charging fidelity to the otherwise promiscuous, unmodified enzyme. Strains incapable of tRNA mismethionylation are less adept at growth in the presence of antibiotics and stressors. The presence of tRNA mismethionylation and its potential role in mistranslation within the bacterial domain establishes this response as a pervasive biological mechanism and connects it to diverse cellular functions and modes of fitness.
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Affiliation(s)
- Michael H Schwartz
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA.,Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
| | - Jacob R Waldbauer
- Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, USA
| | - Lichun Zhang
- Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, USA
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA .,Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
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34
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Determining the fidelity of tRNA aminoacylation via microarrays. Methods 2016; 113:27-33. [PMID: 27639882 DOI: 10.1016/j.ymeth.2016.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/30/2016] [Accepted: 09/12/2016] [Indexed: 12/28/2022] Open
Abstract
The fidelity of tRNA aminoacylation is a critical determinant for the ultimate accuracy of protein synthesis. Although aminoacyl-tRNA synthetases are assumed to consistently maintain high tRNA charging fidelity, recent evidence has demonstrated that the fidelity of the aminoacylation reaction can be actively regulated and liable to change. Accordingly, the ability to conveniently assay the fidelity of tRNA charging is becoming increasingly relevant for studying mistranslation. Here we describe a combined radioactivity and microarray based method that can quantitatively elucidate which individual cognate or noncognate tRNA isoacceptors are charged with amino acid. In this technique, in vitro tRNA charging reactions or in vivo pulse-labeling is performed using a radiolabeled amino acid and tRNA microarrays are used to distinguish tRNA isoacceptors in total tRNA. During the tRNA array hybridization, each tRNA will hybridize to its unique probe and subsequent phosphorimaging of the array can determine which tRNAs were aminoacylated with the radiolabeled amino acid. The method can be used to assess the fidelity of tRNA charging in vivo or in vitro and can be applied to any organism with annotated tRNA genes.
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35
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Fan Y, Evans CR, Ling J. Reduced Protein Synthesis Fidelity Inhibits Flagellar Biosynthesis and Motility. Sci Rep 2016; 6:30960. [PMID: 27468805 PMCID: PMC4965754 DOI: 10.1038/srep30960] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/12/2016] [Indexed: 01/02/2023] Open
Abstract
Accurate translation of the genetic information from DNA to protein is maintained by multiple quality control steps from bacteria to mammals. Genetic and environmental alterations have been shown to compromise translational quality control and reduce fidelity during protein synthesis. The physiological impact of increased translational errors is not fully understood. While generally considered harmful, translational errors have recently been shown to benefit cells under certain stress conditions. In this work, we describe a novel regulatory pathway in which reduced translational fidelity downregulates expression of flagellar genes and suppresses bacterial motility. Electron microscopy imaging shows that the error-prone Escherichia coli strain lacks mature flagella. Further genetic analyses reveal that translational errors upregulate expression of a small RNA DsrA through enhancing its transcription, and deleting DsrA from the error-prone strain restores motility. DsrA regulates expression of H-NS and RpoS, both of which regulate flagellar genes. We demonstrate that an increased level of DsrA in the error-prone strain suppresses motility through the H-NS pathway. Our work suggests that bacteria are capable of switching on and off the flagellar system by altering translational fidelity, which may serve as a previously unknown mechanism to improve fitness in response to environmental cues.
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Affiliation(s)
- Yongqiang Fan
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Christopher R Evans
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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